Analog instruments in motor vehicles for indicating speed or fuel level, for example, generally use a gauge comprising an electrically driven armature which moves a pointer around a dial. An electrical analog signal proportional to the parameter measured ideally drives the pointer to an angular position representing the parameter. It is becoming a common practice to sample the various input signals by a microcontroller which then controls the respective gauges.
The microcontroller is coupled to each gauge by a respective digital driver, typically a low resolution driver which has a limited number of position outputs, so that gauge movement is incremental or step-wise rather than a smooth continuous motion. This stepping or "ticking" is particularly objectionable during slow gauge movement. The limited number of driver position outputs also requires the gauge, when stationary, to indicate one of these positions even though the input signal represents a value between two adjacent positions, thus causing a gauge error except when the input signal happens to coincide with one of the fixed positions.